The Human T-Lymphotropic virus Type-I (HTLV), is a human RNA retrovirus that is known to cause adult T-cell leukemia and lymphoma. The HTLV-II virus shares approximately 70% genomic homology with HTLV-I. HTLV-II is found predominately in IV drug users and Native Americans, as well as Caribbean and South American Indian groups.

Many test methodologies are available worldwide for the serology of HTLV-I/II. The preferred method in the United States (U.S.) is use of an enzyme immunoassay (EIA) recommended by the FDA. EIAs are fast, efficient and allow for a quick turn-around-time for screening anti-HTLV-I/II.

The MP Diagnostics HTLV Blot 2.4 is a qualitative enzyme immunoassay for the in vitro detection of antibodies to HTLV-I and HTLV-II in human serum or plasma. It is intended for use as a more specific supplemental test on human serum or plasma specimens found repeatedly reactive using screening procedures like the Enzyme-Linked Immunosorbent Assays (ELISA).